Catheters are commonly used as channels to inject medications or retrieve fluid samples in a patient. Each catheter comprises a tube, usually derived from plastic or other polymers, such as silicone, polyurethane, and the like, that is inserted into an area of the body and may contain one or more separate lines in which these fluids may be delivered or retrieved. A “lumen” designates a pathway in the catheter that goes from outside the body to inside the body. Catheters are used in various applications, including intravascularly, abdominally, urologically, gastrointestinally, ophthalmically, within the respiratory tract, within cranial space, within the spinal column, and the like. In all cases, the catheter is placed inside of a space in the body where the catheter resides, herein referred to as a “body cavity”. These devices frequently give rise to infections caused by growth of infectious agents in, on, and around the catheter. Infectious agents can include bacteria, fungi, viruses, or the like that enter the body and lead to illness of a patient. Depending on the location of the catheter placement, these infections can arise in the form of urinary tract infections, blood stream infections, soft tissue infection, and the like.
Catheter related infections (CRIs) are a large problem in medicine, leading to high morbidity and mortality rates. Current methods of reducing or eliminating the number of infectious agents in and on a catheter are of low efficacy. Typically, catheters will be removed if they are suspected to be harboring infectious agents, increasing both the cost associated with treatment and patient discomfort. Various methods to deter or eliminate growth of infectious agents in catheters have been attempted, such as using sterile handling techniques, antibiotics, and replacing the catheter when an infection is suspected. Despite these techniques, infections resulting from catheters remain a major problem. According to the Centers for Disease Control and Prevention, over 31,000 people died specifically from catheter-related bloodstream infections in 2010. These infections, along with urinary tract infections, gastrointestinal infections, and other infections from catheters, increase both medical costs and patient discomfort.
Catheters come in various sizes. Those that are smaller in diameter, such as many PICC lines (peripherally inserted central catheters), have small diameter lumens. Such smaller diameter catheters may be suitable for prolonged insertion. Consequently, with smaller diameter catheters, there may be inadequate thickness to the catheter wall to carry a sterilization and/or healthy growth enhancing delivery system.
The use of ultraviolet (UV) light, disinfecting chemicals, catheters impregnated with drugs, to name a few, have been attempted to reduce the prevalence of infection. Many patents have attempted to utilize UV light to disinfect catheters. Unfortunately, UV light is well known to cause damage to living cells. Methods to disinfect connectors, stopcocks, and valves using sterilizing electromagnetic radiation (EMR) have also been attempted using 405 nm light to sterilize these points, but these methods neglect disinfection of the catheter body as well as the tip of the catheter.
The emergence of infectious agents that are resistant to current treatments, such as methicillin-resistance staphylococcus aureus (MRSA), further substantiate the need for another treatment of CRIs. To reduce the costs associated with having to remove and replace the catheters from the patient, there is a need for a catheter that can be sterilized while residing in the patient. Additionally, it would be advantageous to be able to stimulate healthy cell growth by providing therapeutic EMR via the indwelling catheter.
Immediate disinfection after placement could help prevent the growth of biofilm on the catheter. Biofilm consists of extracellular polymeric material created by microorganisms after they adhere to a surface. This biofilm facilitates the growth of infectious agents and is very difficult to break down once it has begun to grow.
The growth of infectious agents can result from agents outside the patient (at the point of access as the catheter crosses the skin or from the catheter hub) or from inside the patient, wherein infectious agents already in the body attach to the surface of the catheter and proliferate. Scientific literature suggests that approximately 65% of CRI's come from infectious agents residing on the skin of the patient (S. Öncü, Central Venous Catheter—Related Infections: An Overview with Special Emphasis on Diagnosis, Prevention and Management. The Internet Journal of Anesthesiology. 2003 Volume 7 Number 1). These agents travel down the outside of the catheter and colonize the catheter tip. For short term catheterization, this is believed to be the most likely mechanism of infection (Crump. Intravascular Catheter-Associated Infections. Eur J Clin Microbiol Dis (2000) 19:1-8). Thirty percent (30%) of CRIs are believed to come from a contaminated hub, in which infectious agents travel down the interior of the catheter (Öncü). This is believed to be the most likely mechanism of infection for long-term catheterization (Crump).
EMR in the range of 380-900 nm has been shown to be effective in killing infectious agents. Research done by a group at the University of Strathclyde shows that light in this range is effective in killing surface bacteria in burn wards without harming the patients (Environmental decontamination of a hospital isolation room using high-intensity light. J Hosp Infect. 2010 November; 76(3):247-51). Published patent application 2010/0246169, written by the members who conducted the study, utilizes ambient lighting to disinfect a large surrounding area. The mechanism proposed by the team suggests that light in this range leads to photosensitization of endogenous porphyrins within the bacteria, which causes the creation of singlet oxygen, leading to the death of the bacteria. (Inactivation of Bacterial Pathogens following Exposure to Light from a 405-Nanometer Light-Emitting Diode Array. Appl Environ Microbiol. 2009 April; 75(7): 1932-7).
Heretofore, however, there has never been apparatus or methods for making or using such apparatus to safely and effectively disinfect a catheter while it is still implanted in a patient. Accordingly, there exists a need for a methods and apparatus designed to deliver non-antibiotic, bactericidal therapeutics in-vivo. Such a methods and apparatus, using novel technology, may provide removable delivery of safe, effective, and reproducible disinfection and/or enhance healthy cell growth.